Such air valves control are well known and are in particular described in DE 100 20 041 C2. The connection between the pressure side and the intake side of a boost pressure pump of a turbocharger via a bypass line is required for a transition from high load to overrun conditions of the internal combustion engine in order to prevent a high delivery rate of the boost pressure pump against a closed throttle flap, and the resultant pumping effects as well as a sudden excessive decrease in the turbo-speed resulting in thermodynamics problems. The air control valve described in DE 100 20 041 C2 comprises pressure compensation bores which ensure a pressure balance at the valve closing body in the closed position despite the pressure difference between the pressure side and the intake side of the boost pressure pump.
Since a calculation of the pressure balance is based on all pressure-loaded surfaces, the air control valve shown in FIG. 2 of the above cited patent can merely use the channel leading to the intake side as a valve seat since a cooperation of the valve with the channel leading to the pressure side would require a different configuration of the membrane 25.
It is therefore an object of the invention to provide an air control valve which is capable of cooperating with both the pressure side of the boost pressure pump and the intake side.